Losing power mystery

I have a 98 Tacoma 2.7 5 speed. Here lately it has been acting up with acceleration. When accelerating, it's jumpy and not smooth with power. Boggs down when pressing peddle down further. It really starts spitting more around the 2 rpm range. Truck is drivable, idles and starts correctly. I changed spark plugs, wires, coil packs, and changed my fuel filter. Air filter is clean. I'm assuming I could have injector going out. I've used several fuel system cleaners with no luck. I wouldn't think this would be a mass air intake sensor, because truck still idles fine... Could try cleaning throttle body... Any suggestions? Thanks

 

Check the grounds in the engine bay.

 

Is it throwing a code? I had similar performance from a bad injector and one time from a bad MAF sensor.

 

When was the timing chain/belt done?

A worn key way on the crank can make the timing bounce back and forth causing sputtering, power fall off, poor acceleration....etc

So can a stretched chain or worn belt...

 

I’m going to see if it’s throwing a code tomorrow. Right now, I just did preventative maintenance, and to see if that would work first, cuz it needed a tune up. Engine has 170,000 miles, would timing chain be an issue around that mileage? 98 has a chain not belt right?

 

If it idles fine, I don't see the timing chain as the primary cause.
My first thought was coil or wires. But you changed that.
This Toyota mechanic "Timmy The Toolman"
has a lot of great Toyota Truck videos.
Try his library.
https://www.youtube.com/user/mtbtim65

 

Partially clogged catalytic converter?
Would have drivability issues when accelerating and cruising.

 

Just out of curiosity, would a bad or disconnected ground have an effect on overall performance like this? I discovered awhile back that my firewall ground (back of the block to the firewall) was badly burnt up, I replaced it with some thick gauge wire but I don't know how long it was like that for. Didn't notice any weird issues with the truck or anything. There are 3 (?) grounds in the engine bay right? Battery, back of the block, and one near the starter I think?

 

my internet guess is the TPS... throttle position sensor.

 

Thanks everyone for the help! I still haven’t narrowed it down. Truck is throwing a code PO171. Maybe has a leak somewhere. Sprayed starting fluid around vacuum hoses, never stirred the idling. I think the grounds are good.. maybe just bad throttle body insides? I unplugged MAF sensor, truck shuts off. Still think it may could be the TPS sensor... where should I throw my money next?

 

Try cleaning the MAF sensor with MAF cleaner (don't use generic electronics cleaner). My money is almost always on a small vacuum leak with P0171 codes unless they're in combination with other codes. But cleaning the MAF is an easy way to rule out a dirty one, unless it's just bad and needs to be replaced (in which case go with a Denso one, not something aftermarket). These trucks won't run without the MAF plugged in.

Good luck...P0171 code is a bitch.

 

Mine was doing something like that back when my fuel pump was taking a dump. Mechanic said it wasn't able to keep up with fuel demand.

 

at this point in time my recommendation is to take her to a shop that has worked on Tacomas before... tell us where you live and maybe someone can point you to a good shop that they know of. Throwing parts at it hoping that it gets fixed just makes you poorer and upset.